The proportion of the world's population over age 60 is increasing at an unprecedented rate. Given this trend, it is imperative to study the mental and physical health of older adults. Psychosocial factors, such as loneliness, are critical in understanding the overall health of older adults, given that increased feelings of loneliness have been linked to functional decline and increased risk of mortality in older adults. Loneliness in older adults may be partially driven by disruptions in meaningful social engagement. In fact, generativity defined as concern and activity dedicated to the well-being of others, especially younger generations and its related components, such as feeling socially useful or needed, are often included in models of successful aging. Furthermore, greater perceptions of generativity have been linked to better health outcomes and longevity in older adults. Thus, lonely older adults may especially benefit from a targeted psychological intervention aimed at increasing perceptions of generativity, which may improve feelings of social connection through increased feelings of social usefulness, as well as improve health outcomes. The objective of this NIA R03 application is to investigate the relationships between social psychological processes and pro-inflammatory responses in the context of health and aging. To do so, the proposed study will investigate the effect of an intervention aimed at increasing perceptions of generativity in lonely older adults on physical and mental health outcomes. Given that pro-inflammatory activity has been linked to both loneliness and poor health outcomes, the study will also examine the effect of the intervention on biological markers of inflammation (i.e., circulating and stimulated pro-inflammatory cytokines and pro-inflammatory gene expression). Participants (n=70) will be randomly assigned to a 6-week intervention aimed at increasing perceptions of generativity or a control condition. During pre- and post-intervention sessions, all participants will complete self-report measures of physical and mental health and have blood drawn (in order to assess biological markers of inflammation). It is hypothesized that participants in the generativity intervention, compared to those in the control condition, will show: 1) improved physical and mental health outcomes and 2) decreased pro-inflammatory activity from pre- to post-intervention. Furthermore, it is hypothesized that decreases in biological pro-inflammatory activity will mediate improvements in health outcomes. The present study will help advance the understanding of the impact of generativity on the lives of older adults, including its effects on health and inflammatory activity. This may inform a low-cost and low-effort way to improve health outcomes in older adults, especially those who may be most vulnerable to poor health outcomes, such as those who are lonely.